Given that lead is detrimental to the human body and could cause environmental pollution, it is demanded in many fields that the use of lead be stopped. For example, in Europe, there are restrictions on lead use in in-vehicle electronic components. With respect to mechanical components and the like, it is often difficult to visually determine whether or not lead is used in parts thereof. Thus, detection methods have been proposed where easy visual detection of lead is made possible by way of chemical reactions. For example, a lead testing kit based on the lead and rhodizonate ion reaction system is available from HybrilVet Systems, Inc. of the United States under the brand “Lead Check(trademark).” In this kit, two types of reagents (sodium rhodizonate and a tartrate buffer) are used. The surface to be tested is rubbed with the tip of a swab saturated with the mixed reagents. By observing for a change in the color of the swab tip caused thereby, the presence of lead is detected. A color change to pink or red indicates the presence of lead, and the lack of any color change indicates the absence of significant levels of lead.
As another example, Patent Document 1 discloses, as a lead detection method suitable for the detection of lead contamination present on the surface of human skin, a method for detecting the presence of lead, comprising: wiping with a handwipe the surface (skin) suspected of lead contamination; solubilizing any lead collected on the handwipe with an acidic aqueous solution; and then treating the solubilized lead ions with rhodizonate ions.
Patent Document 1: WO 98/57167